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Early on August 2, 2014, in the city of Toledo, Ohio, a media alert informed the public that traces of microcystin, a hazardous toxin, had been detected in the drinking water. The warning stated that residents should not drink, boil, or even touch the contaminated water. A water crisis of this magnitude was recognized to pose a potentially serious and significant impact on patient care and safety in health care environments. ProMedica Toledo Hospital’s Emergency Operation Plan addressed 3 critical issues: safe water availability, alternate cleaning solutions, and preparations for a prolonged crisis. This report details some of the lessons learned throughout the response to the crisis: particularly, because the impact was county-wide which affected other hospitals who used the same vendors, alternate water sources should have been secured in advance; the courier service was vital to delivery of supplies and moving equipment to alternate areas for sterilization processes; and finally, communication with staff and patients was jeopardized by external media outlets. Changes to the emergency plan considering these unanticipated aspects proved useful in a later incident and should be considered by all health care facilities as water emergency policies and procedures are created and reviewed. (Disaster Med Public Health Preparedness. 2018;page 1 of 3)

Campylobacteriosis, the most frequent bacterial enteric disease, shows a clear yet unexplained seasonality. The study purpose was to explore the influence of seasonal fluctuation in the contamination of and in the behaviour exposures to two important sources of Campylobacter on the seasonality of campylobacteriosis. Time series analyses were applied to data collected through an integrated surveillance system in Canada in 2005–2010. Data included sporadic, domestically-acquired cases of Campylobacter jejuni infection, contamination of retail chicken meat and of surface water by C. jejuni, and exposure to each source through barbequing and swimming in natural waters. Seasonal patterns were evident for all variables with a peak in summer for human cases and for both exposures, in fall for chicken meat contamination, and in late fall for water contamination. Time series analyses showed that the observed campylobacteriosis summer peak could only be significantly linked to behaviour exposures rather than sources contamination (swimming rather than water contamination and barbequing rather than chicken meat contamination). The results indicate that the observed summer increase in human cases may be more the result of amplification through more frequent risky exposures rather than the result of an increase of the Campylobacter source contamination.

To achieve a reliable radiocarbon (14C) date for an object, any contamination that may be of a different age must be removed prior to dating. Samples that have been conserved with treatments such as adhesives, varnishes or consolidants can pose a particular challenge to 14C dating. At the Oxford Radiocarbon Accelerator Unit (ORAU), common examples of such substances encountered include shellac, the acrylic polymers Paraloid B-67 and B-72, and vinyl acetate-derived polymers (e.g. PVA). Here, a non-carbon-containing absorbent substrate called Chromosorb® was deliberately contaminated with a range of varieties or brands of these conservation treatments, as well as two cellulose nitrate lacquers. A selection of chemical pretreatments was tested for their efficiency at removing them. While the varieties of shellac and Paraloid tested were completely removed with some treatments (water/methanol and acetone/methanol/chloroform sequential washes, respectively), no method was found that was capable of completely removing any of the vinyl acetate-derived materials or the cellulose nitrate lacquers. While Chromosorb is not an exact analog of archaeological wood or bone, for example, this study suggests that it may be possible to remove aged shellac and Paraloid from archaeological specimens with standard organic solvent-acid-base-acid pretreatments, but it may be significantly more difficult to remove vinyl acetate-derived polymers and cellulose nitrate lacquers sufficiently to provide reliable 14C dates. The four categories of conservation treatment studied demonstrate characteristic FTIR spectra, while highlighting subtle chemical and molecular differences between different varieties of shellac, Paraloid and cellulose nitrate lacquers, and significant differences between the vinyl acetate derivatives.

Contamination of feedstuffs and ingredients with heavy metals poses a major problem for animal health and the transmission of toxic substances within the human food chain, as these elements can be accumulated into meat, egg and milk products. This paper reports on the levels of the three metals, arsenic, cadmium and lead, that exceed EU permitted levels, within premixes and complete feeds (total of 3417 samples) destined for a variety of animal species and taken from different countries during the period 2009–2016. For this period, 20% of all samples were contaminated at levels above the EU limit. In complete feed, ruminants were at the highest risk of exposure with 47% of samples being contaminated. Lead posed the major risk for minerals and cadmium posed the highest risk for premixes during the sampling period. When compared by country, contamination levels varied widely, with the highest contamination determined for Canada with 50% of samples being above the EU limit. To mitigate problems with heavy metals in animal feeds, due diligence in terms of sampling and testing is a necessary tool to evaluate level of risk. Research has shown that trace minerals can be sources of these heavy metals so the industry should be more diligent regarding their provider's quality guarantees. In addition, feeds identified with contamination should not be fed to animals to ensure that these heavy metal toxins are not passed into edible food products, thus providing safety in the food chain.

The main objective of this report is to present the dating process routinely applied to different types of samples at the Laboratoire de Mesure du Carbone 14 (LMC14). All the results and protocols refer to our procedures over the last 5 years. A description of the sorting and chemical pretreatments of the samples as well as the extraction and graphitization of CO2 are reported. Our last study concerning the degradation of the blank level according to the storage time of the targets between graphitization and accelerator mass spectrometry (AMS) measurement is also presented. This article also provides information on how to submit a valid laboratory sample. We give details relating to sampling procedures on site as well as contamination issues relative to the 14C dating methodology.

Information on the dissipation of clomazone, imazapyr, and imazapic in paddy water under different irrigation system is not available in the literature. The objective of this study was to investigate the effect of two irrigation systems (intermittent (IF) and continuous (CF) flood) on the dissipation of clomazone, imazapyr, and imazapic in paddy water. Imazapic was the least persistent herbicide in paddy water, with DT50-values of approximately 3 and 5d under CF and IF, respectively. Imazapyr required a two-fold increase in time to reach its half-life in water in contrast to imazapic, with DT50-values of approximately 6 and 11d under CF and IF, respectively. Clomazone showed the highest DT50-values, varying between 7 to 21d under CF and IF, respectively. Imazapyr and imazapic dissipation was faster under CF, while clomazone was not affected. This investigation found that the dissipation behaviors of herbicides vary under different rice irrigation regimes. Thus changes in irrigation management, as will be required to produce more rice grain with less water to avoid future scarcity, should consider impacts of flood management on herbicide persistence and environmental behavior.

The introduction of soybean and cotton traits with resistance to synthetic auxin herbicides has led to an increase in concern over the off-target movement of dicamba and 2,4-D. A direct-mail survey was sent to Missouri pesticide applicators in January of 2016 to understand current herbicide application practices and applicator knowledge and awareness of the new synthetic auxin technologies. Completed surveys were returned by 2,335 applicators, representing approximately 11% of the state’s registered pesticide applicators. Survey data reported herein provides information regarding current pesticide applicator knowledge and practices and highlights areas that need more emphasis during applicator training. Overall, survey respondents were familiar with physical drift and methods to minimize that risk. However respondents were less familiar with volatility and temperature inversions, which can each influence off-target herbicide movement. Of the 427 commercial applicators and 1,535 noncommercial applicators who answered questions regarding volatility, 81% and 74% respectively, recognized that high temperatures can contribute to a herbicide’s ability to volatilize. However, only 48% and 39% understood that a herbicide’s vapor pressure influences volatility. Answers from the survey indicate further education is needed on the synthetic auxin technologies, such as what herbicides can be used with each technology, proper methods for inspecting and cleaning spray equipment, and the importance of reading herbicide labels. When asked whether applicators were aware of the new 2,4-D-resistant and dicamba-resistant traits, 76% of 443 commercial applicators and only 40% of 1,713 noncommercial applicators selected “yes.” Additionally, survey results suggests that current methods aimed to facilitate communication among producers and applicators, such as FieldWatch and Flag the Technology, may not be successfully adopted, at least in Missouri. Findings from this survey can be utilized to enhance training of pesticide applicators in preparation for the synthetic auxin herbicide technologies.

Synthetic rubbers, synthetic plastic polymers (polyvinyl chlorides [PVC]), polyurethane blends, and polyethylene blends make up modern-day agricultural spray hoses. The objective of this study was to determine whether agricultural hose types would differ with respect to 3,6-dichloro-2-methoxybenzoic acid (dicamba) sequestration. Field and greenhouse studies were conducted to evaluate the sequestration potential of dicamba within five agricultural hose types when cleaned with different cleanout procedures. Rinsate solutions were applied to soybean, which was used as a bio-indicator to test for cleanout efficiency. Differences among hose types and cleanout procedures exist with observations including soybean injury, height reduction, dry matter, yield, and part per million by volume (ppmv) analyte retained. The makeup of PVC polyurethane-blend and synthetic rubber–blend hoses increased retention of dicamba analyte when compared with the polyethylene blend hose. No differences were observed after the addition of ammonia to the cleanout solution when compared with water alone. Differences in a hose type’s ability to sequester the dicamba analyte may have more to do with the hose’s internal chemical composition, manufacturing process, and composition breakdown. Scanning electron microscopy revealed imperfections in new PVC polyurethane and synthetic rubber hoses that eventually lead to inner wall depletion of these hose types. This is in contrast to what was found in the polyethylene-blend hose type, in which the inner wall is smooth and free of imperfections.

At INFN-LABEC (Florence, Italy), a new pretreatment for radiocarbon dating based on chloroform has been recently set up. This method aims to remove the synthetic resins used for artwork restoration, which otherwise could alter the original 14C content. The present study characterizes the efficiency of the process when applied to wood. We have verified whether the effectiveness of the pretreatment depends on the number of extractions in chloroform. We prepared samples by applying different volumes of Paraloid B-72®, one of the most widespread products used in restoration, on poplar wood of known age. Contaminated samples were artificially aged in a climatic chamber. A fraction from each sample was collected before any treatment and after respectively 1, 2, 3, and 4 extractions in chloroform, and 14C dating by AMS, the resin appears to be already removed after the first two extractions. Furthermore, the extracted mixtures of chloroform and possible removed Paraloid were measured by FTIR spectroscopy, the results of which confirmed the 14C results. The efficiency of the pretreatment was also verified on historical wooden materials that had been previously restored. In these cases, a higher number of extractions is required, suggesting a careful approach when dealing with “real” artworks.

Substances enriched with radiocarbon can easily contaminate samples and laboratories used for natural abundance measurements. We have developed a new method using wet chemical oxidation for swabbing laboratories and equipment to test for 14C contamination. Here, we report the findings of 18 months’ work and more than 800 tests covering studies at multiple locations. Evidence of past and current use of enriched 14C was found at all but one location and a program of testing and communication was used to mitigate its effects. Remediation was attempted with mixed success and depended on the complexity and level of the contamination. We describe four cases from different situations.

A series of experiments was carried out previously on board of the International Space Station in ‘EXPOSE-R’, a multi-user expose facility, provided by European Space Agency attached to the external surface of the Russian Segment. In one experiment, spores of microorganisms and species of higher plant seeds, in heat-sealed polymer bags were irradiated by solar radiation passed through MgF2 windows in a high space vacuum. After sample exposure, it was found that in many cases the inner surfaces of windows were contaminated. Analysis of the contamination revealed the presence of chemical groups CH2, CH3, NH, OH, C═O, Si–CH3 (Demets et al. in 2015). Their presence in deposits was explained by photofixation of gaseous precursors – some of the vapours of glues and additives in polymeric materials in the core facility of ‘Expose-R’. Carbon-, oxygen- and silicon-containing groups may be deposited from outer intrinsic atmosphere. This atmosphere is connected with sample compartments and core facility. However, the presence of NH groups on inner surfaces of windows was not expected. This paper shows that the process responsible for carbon-, nitrogen- and oxygen-containing group formation can be a photopolymerization of caprolactam, which is released from the outer Nylon 6 layer of polymer bags under Solar vacuum ultraviolet radiation.

The present study aimed to assess the safety of gluten-free bakery products for consumption by coeliac patients.

Design/setting

In the current exploratory cross-sectional quantitative study, a total of 130 samples were collected from twenty-five bakeries in Brasilia (Brazil). For the quantification of gluten, an ELISA was used. The threshold of 20 ppm gluten was considered as the safe upper limit for gluten-free food, as proposed in the Codex Alimentarius.

Results

The results revealed a total of 21·5 % of contamination among the bakery products sampled. Sixty-four per cent of the bakeries sold at least one contaminated product in our sample.

Conclusions

These findings represent a risk for coeliac patients since the ingestion of gluten traces may be sufficient to adversely impact on their health.

Given the centrality of utopia to the African literary and postcolonial imaginary, science fiction by African writers offers a unique opportunity to explore and critique the sociopolitical salience of imagined African futures. Through a close reading of three short stories in the AfroSF: Science Fiction by African Writers Vol I (2012) anthology, I illustrate how generic science fiction utopias prove to be much too sterile when applied to an African context and thus do not amount to a viable and sustainable future. Making use of tropes of contagion, there is a clear desire to demonstrate that the human impulse is, in many ways, contrary to the objectives of neat utopias and these stories subsequently seek to “contaminate” the notion of utopia itself. Overall, I suggest that this is indicative of a shifting postcolonial landscape that needs to more carefully weigh the price of its utopias.

Development of shale gas by hydraulic fracturing (‘fracking’) is opposed by campaigners who propose (inter alia) that freshwater aquifers could be polluted by upward migration of fractures and any fluids they contain. Prima facie hydrogeological analysis of this proposition has been undertaken. For it to occur, two conditions must be satisfied:
(i)

With regard to (i), shale gas developers have a major vested interest in avoiding creating such hydraulic connection, as it would result in uneconomically excessive amounts of water needing to be pumped from their wells to achieve gas production. In relation to (ii), nominal upward hydraulic gradients will typically only be developed during fracking for periods of a few hours, which is far too brief to achieve solute transport over vertical intervals of one or more kilometres; thereafter, depressurisation of wells to allow gas to flow will result in downward hydraulic gradients being maintained for many years. The proposition is therefore found to be unsupportable. Albeit for contrasting motivations, developers and environmental guardians turn out to have a strong common interest in avoiding inter-connection to aquifers.

A powerful illustration of the potential long-term effects of fracking is provided by the hydrogeological history of underground coal mining in the UK. Where large-scale mining proceeded from the surface downwards, major hydraulic inter-connection of shallow and deep zones resulted in widespread water pollution. However, where new mines were developed at depth without connections to shallow old workings (as in the Selby Coalfield, Yorkshire), complete hydraulic isolation from the near-surface hydrogeological environment was successfully maintained. This was despite far greater stratal disruption and induced seismicity than shale gas fracking could ever produce. The lesson is clear: without hydrogeological connectivity to shallow aquifers, shale gas fracking per se cannot contaminate shallow ground water.

Accelerator mass spectrometry (AMS) measurements of the radiocarbon content in very old samples are often challenging and carry large relative uncertainties due to possible contaminations acquired during the preparation and storage steps. In case of such old samples, the natural surrounding levels of 14C from gases in the atmosphere, which may well be the source of contamination among others, are 2–3 orders of magnitude higher than the samples themselves. Hence, serious efforts are taken during the preparation steps to have the samples pristine until measurements are performed. As samples often have to be temporarily stored until AMS measurements can be performed, storage conditions also become extremely crucial. Here we describe an assessment of this process of contamination in background AMS samples. Samples, both as pressed graphite (on AMS targets) and graphite powder, were stored in various storage conditions (CO2-spiked air) to investigate the extent of contamination. The experiments clearly show that the pressed targets are more vulnerable to contamination than the unpressed graphite. Experiments conducted with enriched CO2-spiked laboratory air also reveal that the contaminating carbon is not only limited to the target surface but also penetrates into the matrix. A combination of measurements on understanding the chemical nature of the graphitization product, combined with long-available knowledge on “adventitious carbon” from the surface science community, brought us to the conclusion that contamination is to a certain extent inevitable. However, it can be minimized, and should be dealt with by sputter-cleaning the samples individually before the actual measurement.

Fifty six sediment cores were collected along a 100 km longitudinal transect of the Thames estuary. Total Hg ranged from 0.01 to 12.07 mg/kg, with a mean of 2.10 mg/kg (n=351). Concentrations of the toxic metal decreased downstream from London to the outer estuary and were positively correlated to total organic carbon (TOC) content. Many Hg profiles showed a clear rise, peak and fall, reflecting changing anthropogenic input through time. Surface concentrations averaged 1.27 mg/kg, confirming the effectiveness of recent environmental legislation and improved river management. Sediments at >40 cm depth from London reaches of the river (Waterloo Bridge, Cuckolds Point (Rotherhithe), Butlers Wharf (Tower Bridge), Millwall, Deptford and Millennium Dome) were highly contaminated, with levels of Hg of >7 mg/kg. The outer Thames had lower Hg, with the exception of Rainham, Crossness and Cliffe. Benchmarking against UK guidelines for the disposal of dredged material revealed that 88 samples from 21 sites exceeded the 3 mg/kg criteria (unsuitable for disposal at sea); 173 fell between 0.3 and 3 mg/kg (further assessment required); and 90 were of no concern. Using Hg as a generic pollution marker, the tidal Thames is one of the world's most contaminated river–estuarine sediment systems.

Listeria monocytogenes is a foodborne pathogen that can cause bacteraemia, meningitis, and complications during pregnancy. In July 2012, molecular subtyping identified indistinguishable L. monocytogenes isolates from six patients and two samples of different cut and repackaged cheeses. A multistate outbreak investigation was initiated. Initial analyses identified an association between eating soft cheese and outbreak-related illness (odds ratio 17·3, 95% confidence interval 2·0–825·7) but no common brand. Cheese inventory data from locations where patients bought cheese and an additional location where repackaged cheese yielded the outbreak strain were compared to identify cheeses for microbiological sampling. Intact packages of imported ricotta salata yielded the outbreak strain. Fourteen jurisdictions reported 22 cases from March–October 2012, including four deaths and a fetal loss. Six patients ultimately reported eating ricotta salata; another reported eating cheese likely cut with equipment also used for contaminated ricotta salata, and nine more reported eating other cheeses that might also have been cross-contaminated. An FDA import alert and US and international recalls followed. Epidemiology-directed microbiological testing of suspect cheeses helped identify the outbreak source. Cross-contamination of cheese highlights the importance of using validated disinfectant protocols and routine cleaning and sanitizing after cutting each block or wheel.

Expose is a multi-user instrument for astrobiological and astrochemical experiments in space. Installed at the outer surface of the International Space Station, it enables investigators to study the impact of the open space environment on biological and biochemical test samples. Two Expose missions have been completed so far, designated as Expose-E (Rabbow et al. 2012) and Expose-R (Rabbow et al. this issue). One of the space-unique environmental factors offered by Expose is full-spectrum, ultraviolet (UV)-rich electromagnetic radiation from the Sun. This paper describes and analyses how on Expose-R, access of the test samples to Solar radiation degraded during space exposure in an unpredicted way. Several windows in front of the Sun-exposed test samples acquired a brown shade, resulting in a reduced transparency in visible light, UV and vacuum UV (VUV). Post-flight investigations revealed the discolouration to be caused by a homogenous film of cross-linked organic polymers at the inside of the windows. The chemical signature varied per sample carrier. No such films were found on windows from sealed, pressurized compartments, or on windows that had been kept out of the Sun. This suggests that volatile compounds originating from the interior of the Expose facility were cross-linked and photo-fixed by Solar irradiation at the rear side of the windows. The origin of the volatiles was not fully identified; most probably there was a variety of sources involved including the biological test samples, adhesives, plastics and printed circuit boards. The outer surface of the windows (pointing into space) was chemically impacted as well, with a probable effect on the transparency in VUV. The reported analysis of the window contamination on Expose-R is expected to help the interpretation of the scientific results and offers possibilities to mitigate this problem on future missions – in particular Expose-R2, the direct successor of Expose-R.

Transmission electron microscopy (TEM) images of beam sensitive weak-phase objects such as biological cryo samples usually show a very low signal-to-noise ratio. These samples have almost no amplitude contrast and instead structural information is mainly encoded in the phase contrast. To increase the sample contrast in the image, especially for low spatial frequencies, the use of phase plates for close to focus phase contrast enhancement in TEM has long been discussed. Electrostatic phase plates are favorable in particular, as their tunable potential will allow an optimal phase shift adjustment and higher resolution than film phase plates as they avoid additional scattering events in matter. Here we show the first realization of close to focus phase contrast images of actin filament cryo samples acquired using an electrostatic Zach phase plate. Both positive and negative phase contrast is shown, which is obtained by applying appropriate potentials to the phase plate. The dependence of phase contrast improvement on sample orientation with respect to the phase plate is demonstrated and single-sideband artifacts are discussed. Additionally, possibilities to reduce contamination and charging effects of the phase plate are shown.